1. Field of the Invention
The present invention relates to a battery box for containing a plurality of cells and a battery holder for holding the cells.
2. Description of the Related Art
In a known battery structure (refer to a battery structure employed in an electric vehicle, disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 9-86188), (i) a plurality of cylindrical battery cells, held by rib walls, are arranged in a box-shaped battery case in a manner such that the central axes of the battery cells pass through lattice points which are positioned on a specific lattice, and (ii) air vents, through which cooling air passes, are formed in the upper and lower walls (of the battery case) which face each other along the direction perpendicular to the central axes of the battery cells, so as to ventilate the inside of the battery case with the cooling air in the vertical direction and to cool the battery cells held by the rib walls.
In the above-explained conventional battery structure having the air vents provided in the upper and lower walls, the cooling condition is different between the battery cells positioned in the vicinity of the air vents at the cooling-air drawing side and the battery cells positioned in the vicinity of the air vents at the cooling-air discharging side, thereby producing a large temperature difference.
For example, in comparison with the vicinity of the air vents at the cooling-air drawing side, flowability around the battery cells is degraded in the vicinity of the air vents at the cooling-air discharging side, thereby degrading the degree of cooling for the battery cells.
Also in the above-explained conventional battery structure in which a plurality of the battery cells are arranged in a lattice pattern, the battery case should be large and thus it is difficult to improve the flexibility for building the battery case into a vehicle such as an electric car.
In addition, the rib walls for holding the battery cells in the battery case are formed integrally with the battery case; thus, the structure of the battery case is complicated and it is difficult to suitably modify the arrangement of the battery cells in the battery case.
In consideration of the above circumstances, the first object of the present invention is to provide a battery box for containing a plurality of cells and suppressing nonuniformity in the temperature distribution between the cells.
The second object of the present invention is to provide a battery box and a cell holder, by which the battery box for containing a plurality of cells can be smaller and the arrangement of the cells can be flexibly and easily modified.
Therefore, the present invention provides a battery box (e.g., the battery box 10 in an embodiment explained below) comprising:
a container (refer to the internal space 21 in the embodiment explained below) formed by connecting an upper portion (e.g., the upper portion 11 in the embodiment explained below), a lower portion (e.g., the lower portion 12 in the embodiment explained below), a front portion (e.g., the front portion 13 in the embodiment explained below), a rear portion (e.g., the rear portion 14 in the embodiment explained below), and two side portions (e.g., the right portion 15 and the left portion 16 in the embodiment explained below), where the container can be disassembled and the front portion has a coolant supply opening (e.g., each front opening 22 in the embodiment explained below) from which a coolant is drawn into the container, and the rear portion has a coolant discharge opening (e.g., each rear opening 23 in the embodiment explained below) from which the coolant is discharged from the container;
a battery holder (e.g., the battery holder 17 in the embodiment explained below) having a plurality of cell holding members (e.g., the grommets 61, . . . , 61 in the embodiment explained below) for holding a plurality of cells (e.g., the battery cells 18, . . . 18 in the embodiment explained below) in the container, wherein the cell holding members are detachably connected to each other in a manner such that central axes of the cells held by the cell holding members are parallel to a direction along which the two side portions face each other and that the cells are arranged in a zig-zag matrix form in a section perpendicular to the central axes of the cells;
a shielding member (e.g., the first shielding member 43, the second shielding member 44, or the third shielding member 45 in the embodiment explained below), provided in the vicinity of the coolant supply opening, for changing the flow direction of the coolant which is drawn from the coolant supply opening into the container, and for preventing the coolant from directly blowing onto at least one of the cells in the vicinity of the coolant supply opening; and
a flow control member (e.g., the first flow control member 32 or the second flow control member 33 in the embodiment explained below), provided in the vicinity of the coolant discharge opening, for changing the flow direction of the coolant in a manner such that the coolant flows towards the rear side of at least one of the cells in the vicinity of the coolant discharge opening.
According to the above battery box, the cells can be arranged in a zig-zag matrix form by using the cell holding members, so that the arrangement efficiency of the cells in the container can be improved and the battery box can be smaller. In addition, the arrangement density with respect to the cells in the container is relatively increased, and accordingly, even when the volume of the space through which the cooling air passes relatively decreases, the shielding member in the vicinity of the coolant supply opening and the flow control member in the vicinity of the coolant discharge opening prevent nonuniformity in the temperature distribution, thereby improving the cooling efficiency.
That is, the shielding member may be arranged in a manner such that the shielding member interrupts the flow of the coolant, which is directed towards the surface of a cell which faces the coolant supply opening, so as to prevent the coolant from directly blowing onto the cell. In this case, it is possible to prevent (i) the cell in the vicinity of the coolant supply opening from being excessively cooled, and (ii) the temperature of the coolant in the vicinity of the coolant supply opening from excessively increasing.
In addition, in order to improve the cooling efficiency of the coolant in the vicinity of the coolant discharge opening, the flow control member is arranged, which can narrow the coolant passage around a target cell and increase the flow rate of the coolant. Accordingly, desired capability for cooling the cell in the vicinity of the coolant discharge opening can be obtained, thereby suppressing the temperature of the cell in the vicinity of the coolant discharge opening from being relatively increased.
In the above battery box, each of the front and rear portions may have a support portion (e.g., the concave portion 47 and the convex portion 48 in the embodiment explained below) for supporting the battery holder. According to this structure, the battery holder is fixed between the front and rear portions in the container. Therefore, the battery holder can be easily fixed simply by providing the support portion at each of the front and rear portions (i.e., constituents of the container), without providing any additional members between which the battery holder can be fixed.
As a preferable example, each cell holding member of the battery holder has at least a pair of a convex portion (e.g., the convex portion 51 in the embodiment explained below) and a concave portion (e.g., the concave portion 52 in the embodiment explained below) which are provided on an outer surface of the cell holding member; and
the cell holding members are detachably connected to each other by fitting the convex portion of one cell holding member into the concave portion of another cell holding member.
According to this structure, when a plurality of cell holding members are connected to each other, any two cell holding members are fastened to each other by respectively engaging the convex portion and the concave portion of one of the members with the concave portion and the convex portion of the other member. Here, each convex portion is detachably fitted into the concave portion of another cell holding member; thus, the cell holding members can be easily connected or disconnected, and the arrangement of the cell holding members in the container can be easily modified or changed. In addition, if the above support portion provided at each of the front and rear portions is a pair of a convex portion and a concave portion, the front and rear portions can be easily connected to the battery holder and also easily disconnected from the battery holder.
The present invention also provides a battery holder comprising a plurality of cell holding members for holding a plurality of cells, wherein:
the cell holding members are detachably connected to each other in a manner such that central axes of the cells held by the cell holding members are parallel to a direction along which the two side portions face each other and that the cells are arranged in a zig-zag matrix form in a section perpendicular to the central axes of the cells; and
each cell holding member has a ring-shaped member (e.g., the grommet 61 in the embodiment explained below) into which one of the cells is insertable, wherein the ring-shaped member has a contact face (e.g., the contact face 61a in the embodiment explained below) on an outer-peripheral surface (e.g., the outer-peripheral surface 61A in the embodiment explained below) of the ring-shaped member, and the contact face is contactable with the ring-shaped member of another cell holding member when the cell holding members are connected to each other.
According to the above battery holder, the cells can be arranged in a zig-zag matrix form by using the cell holding members, so that the arrangement efficiency of the cells can be improved. Here, each ring-shaped member has a contact face on the outer-peripheral surface of the ring-shaped member. Therefore, when the ring-shaped members are connected to each other, positioning of each member at a specific position can be easily performed by arranging the ring-shaped members in a manner such that the contact faces of each member are made to contact each other.
In a typical example, the battery holder further comprises:
at least one coupling member (e.g., the coupling member 62 in the embodiment explained below) which is provided for connecting two of the ring-shaped members, wherein:
the coupling member has two ends, one end being connected to one of the two ring-shaped members and the other end being connected to the other ring-shaped member, in a manner such that the two ends are both rotatable around a rotation center; and
the contact face of one of the two ring-shaped members is contactable with the contact face of the other ring-shaped member by rotating the two ends.
According to this structure, it is possible to easily make the contact face of one of the ring-shaped members contact the contact face of the other ring-shaped member simply by rotating the two ends of the coupling member. Therefore, the specific positioning of the cell holding members can be more easily performed.
In a preferable example, each ring-shaped member has at least a pair of a convex portion and a concave portion which are provided on the contact face; and
the cell holding members are detachably connected to each other by fitting the convex portion of the ring-shaped member of one cell holding member into the concave portion of the ring-shaped member of another cell holding member.
According to this structure, when a plurality of cell holding members are connected to each other, the cell holding members can be easily fastened to each other simply by making the contact faces of the ring-shaped members contact each other, by which the convex portion and the concave portion of each ring-shaped member are respectively engaged with the concave portion and the convex portion of another member. Here, each convex portion is detachably fitted into the concave portion of another ring-shaped member; thus, the cell holding members can be easily connected or disconnected, and the arrangement of the cell holding members can be easily modified or changed.
Typically, the battery holder is made of an electrically insulating material. In this case, desired electrically-insulating capability can be secured.
In addition, each ring-shaped member may have a protruding portion (e.g., the protruding portion 53 in the embodiment explained below) on an inner-peripheral surface (e.g., the inner-peripheral surface 61B in the embodiment explained below) of the ring-shaped member, wherein the protruding portion contacts an outer-peripheral surface (e.g., the outer-peripheral surface 18A in the embodiment explained below) of the cell inserted into the ring-shaped member.
In this case, a suitable space can be produced between the inner-peripheral surface of the ring-shaped member and the outer-peripheral surface of the cell inserted into the ring-shaped member. In addition, the ring-shaped member contacts the outer-peripheral surface of the cell via the protruding portion; thus, the distance along which the ring-shaped member contacts the outer-peripheral surface of the cell can be increased depending on the shape of the protruding portion, thereby further improving the electrical insulation performance. Furthermore, when the cell is inserted into the ring-shaped member, the ring-shaped member deforms, so that the cell can be easily attached to the ring-shaped member.
The present invention also provides a battery box into which a battery holder as explained in the preferable example is detachably built, the battery box comprising;
a container formed by connecting an upper portion, a lower portion, a front portion, a rear portion, and two side portions, wherein the container can be disassembled and each of the upper, lower, front, and rear portions has an concave portion (e.g., the concave portion 35 or the concave portion 47 in the embodiment explained below) and a convex portion (e.g., the convex portion 36 and the convex portion 48 in the embodiment explained below) which are detachably engaged with the convex portion and the concave portion of the ring-shaped member of one of the cell holding member.
According to the above battery box, the concave portion and the convex portion provided at each of the upper, lower, front, and rear portions has an concave portion can be respectively and detachably engaged with the convex portion and the concave portion provided on each ring-shaped member, so that the battery holder can be easily built into the container and also easily detached from the container.